Morale above 75% does give a Production bonus, up to +25% at 100% morale, as well as a bonus to population growth and resistance. Morale below 75% starts to reduce everything. You can see how much of a bonus you're getting by hovering over Population Growth (which is the only tooltip for morale that works right now).
The reason it doesn't show in the tooltips for most things is that it modifies base production, which is a hidden stat that is expressed to the player as Raw Output. Hopefully that changes in the future.
